Sound reproducing diaphragm



1933. c. M. TICHENOR ET AL ,328

SOUND REPRODUCING DIAPHRAGI Filed Jan. 25, 1933 2 Sheets-Sheet 1 Oct.10, 1933. c. M. TICHENOR ET AL 1,930,328

SOUND REPRODUCING DIAPHRAGM Filed Jan. 25, 1933 2 Sheets-Sheet 2rwewto'bs AD W WWS Patented 0a. 10, 1933 UNITED STA rE-s n 7 1,930,328SOUND ,REPRODU'CING DIAPHRAGM Carl M. Tichenor, Muskegon, and Byron C.Booth, Muskegon Heights, Mich.; said Booth assignor to said TichenorApplication January 25,

11- Claims.

This invention relates to acoustical devices and more particularly toimprovements in sound reproducing diaphragms of the cone diaphragm ortympanum type.-

One of the objects of this invention is to provide a diaphragm capableofreproducing both high and low frequency notes corresponding in intensityand quantity, as well as timbre mellowness and other qualities, with theoriginally produced sound waves. I

Another important object of the invention is to provide a soundreproducing diaphragm of this character in which the greatest frontalarea possible is obtained with a minimum dimension inone direction. I

While the resent invention may obviously be used to advantage numerousand various acoustical or sound reproducing devices, it finds particularutility when used in connection with radios designed for installationeither on the instrument panel or above the windshield ofmotor vehiclesand the like. In the present day commercial type of motor vehicle, theavailable space at the aforementioned points for installation of a loudspeaker or sound reproducing device is limited in one direction, that isin the vertical direction, the'greatest available space being usuallybetween 4 to 5 inches. However, asound reproducing diaphragm of thesedimensions has insufficient workingsurface to properlyproduce the baseor low frequency notes, In order to obtain 1 a desirable base responseit is necessary that at least one dimension of the sound reproducingcone be between 7 to 10' inches. -A sound reproducing diaphragm ofapproximately these dimensions presents a working surface ranging fromapproximately 18 square inches to 30 square inches. A loud speaker witha frontal area within these dimensions will produce results that atpresent are considered commercially satisfactory. i

In accordance with our invention, we provide a sound reproducingdiaphragm substantially conical or dish-shaped having a substantiallyoblong effective outside periphery providingtwo spaced, relatively longsides. With a sound reproducing diaphragm of this character,installation is possible within the restricted areas available at theinstrument panel or above the windshield of a motor vehicle, and at thesame time the required frontal area of the speaker cone is obtained.

The various objects, advantages and novel details of construction of theinvention, as well as several structural embodiments thereof, will be1933. Serial No, 653,540 (01. 181-31) madejmore apparent as thisdescription proceeds, especially whenconsidered in connection with theaccompanying drawingswherein,

Figure 1 is a longitudinal sectional view through a sound reproducingdevice embodying a diaphragm constructed in accordance with thisinvention;

Figure 2 is a plan view of the diaphr trated in Figure 1;

Figure 3 is a sectional view taken substantially onthe plane indicatedby line 3-1-3 in Figure 2;

Figure 4 is a fragmentary perspective view of the diaphragm illustratedin Figure 1; a a

Figure 5is a plan view of a slightly modified form of diaphragm; I A

Figure 6 is a detail sectional view taken substantially on the planeindicated by line6--6 in Figure 5; I Figure 7 is a detail sectional viewtaken substantially on the plane indicated by line 77 in Figure 5;

Figure 8 is a fragmentary end elevational view of the structureillustrated in Figure 5;

Figure 9 is a plan view of still another modifled form of diaphragm; I a

Figure 10 is a sectional view taken substantially on the plane indicatedby line 10'-l0 in Figure 9;

Figure 11 is a sectional view taken substantially on the planeindicatedby line 1l11 in Figure 9; I I

Figure 12 is a fragmentary detail perspective view of a portion of thediaphragm illustrated in Figure 9;' v

Figure 13 is a plan view of still another modified form of diaphragm; r

Figure 14 is a sectional view taken substantially on the plane indicatedby the line 14-14 in Figure 13; v

Figure 15 is a'sectional view taken substantially on the plane indicatedby line 15-15 in Figure 13, and i Figure 16 is a fragmentarydetailperspective view'of the formof construction shown in Figure 13.

Referring now particularly to the drawings and more especially toFigures 1 to 4 thereof, it will be noted that there is'illustrated adiaphragm 10 substantially conical or dish-shaped. This diaphragm isformed of light vibratile material agm illusand may be formed inany'preferred or desired manner. The diaphragm is substantially oblongin plan view to thus provide a pair of spaced parallel sides 11 definingthe shortest dimension of the diaphragm. The reference character 12indicates the effective outside periphery of the diaphragm at the ends.Flat flexible strips 13 are secured to the long side edges 11 of thediaphragm either adhesively or in any other preferred manner, and theends 12 are provided with flexible strips 14, preferably, although notnecessarily, integrally formed therewith.

A supporting spider 15 provides a peripheral mounting for the diaphragm10 and is secured respectively to the flexible strips 13 and 14. If thespeaker is to be mounted in registration with an opening 16 of a baffleboard 17 cushion members or gaskets 18 are interposed (see particularlyFigure 1).

The reference character 19 indicates the shell of the magnet whichcontains a field coil 20 which surrounds the core 21. The referencecharacter 22 indicates the voice coil, and 23 a flexible spider which issecured to the diaphragm adjacent the voice coil andto projections orthe like 15-" formed on the supporting spider 15.

In the form of construction shown in Figures 1 te-4 the diaphragm isdished at its longitudinal peripheral edges 11 and the supporting spider15 has side flanges 24, the free edges of which are arranged insubstantially the same plane as the peripheral end edges of thediaphragm.

Thus far one method of mounting and supporting the: diaphragm has beendescribed somewhat in detail. However, it should be understood that theform of the diaphragm just described, aswell as the modified formshereinafter to be referred to, may be mounted and supported in anypreferred or desired manner, the description in this connection hereinbeing for illustrative purposes only.

With the type of diaphragm thus far described, it will be noted that asubstantially oblong contour is provided in which the two relativelylong spaced edges 11 define the effective outside periphery of thediaphragm in one direction. This dimension of the diaphragm is selectedso as to keepv this cross-sectional area of the diaphragm within suchlimits as to enable the same to be properly installed in the restrictedareas heretofore referred to, or in such other restricted areas as thediaphragm. may be employed. The working surface or frontal areanecessary to a faithful reproduction of the base tones is obtained bythe longer dimension of the cone, the effective outside periphery ofwhich is defined by the end edges 12. e

In Figures 5 to 8 inclusive a slightly modified form of construction isillustrated in which flat flexible strips of leather, fabric, or thelike 25 are provided at the long edges 26 of the diaphragm 27, andsimilar flat flexible strips 28 are provided at the ends thereof inplace of the integral flexible strips 14 shown in the form ofconstruction illustrated in Figures 1 to,4 inclusive. These flexiblemounting strips for the diaphragm may be secured thereto either byadhesive or in any other preferred manner. These flexible strips are inturn secured to a supporting spider 29. The connection with the voicecoil and the other details of the magnet may be similar to the form ofconstruction shown in Figures 1 to 4.

In Figures 9 to 12 still another modified form of construction isillustrated inwhich the cone 30 is provided at its long sides withflexible strips 31 formed preferably integrally therewith and at its endedges with flexible strips 32 preferably formed integrally therewith.The flexible strips 31 and 32 are separated, as at 33, at the juncturethereof to provide for the maximum flexibility.

In this form of construction the flexible diaphragm supporting stripsare all arranged in the same general plane and for this purpose thestrips 31 are provided with right angular flange portions 34 which arejoined to or form continuations of the peripheral edges 35 of thediaphragm.

In Figures 13 to 16 inclusive still another modified form ofconstruction is shown in which thediaphragm 36 is provided with acontinuous flexible supporting strip 37 preferably formed integrallywith the periphery of the diaphragm, the supporting strip at the cornersof the diaphragm being curved on a radius, as indicated at 38, toprovide sufiicient flexibility so as not to retard the vibratorymovement of the diaphragm. In this form of construction, the flexiblediaphragm supporting strip is in the same plane throughout its length.

In each of the. forms. of" construction herein described, the diaphragmis conical in shape to obtain the required rigidity. However, in eachform of construction the effective outside diameter or periphery of thediaphragm is of substantially oblong configuration to produce adiaphragm having one relatively small transverse dimension- Asheretofore mentioned, an adequate frontal area is obtained for allpractical purposes by the extension of the diaphragm in the direction atright angles to this minimum transverse dimension. Thus the diaphragmadapts itself to installation on the instrument panels and header barsof motor vehicles and the like wherein the available space in onedirection is limited.

Inasmuch as the invention herein defined pertains more especially to thediaphragm per se, it will be immediately obvious to those skilled inthis art that the peripheral mounting for the diaphragm, the connectionwith the voice coil, 115 and all otherv details of this character may bemodified as found to be desirable or expedient. Moreover, othermodifications of this invention may suggest themselves to those skilledin this art, and to this end reservation is made to make I such changesas may come within the purview of the accompanying claims- What we claimas our invention is:

1. In an acoustical device, a substantially conical tympanum having asubstantially oblong 125 periphery including two substantially parallelsides.

2. In an acousticaldevice, a substantially conical diaphragm having anoblong periphery including two relatively long parallel sides to providea relatively small frontal area dimension in one direction to permitinstallation on the instrument panels and header bars of motor vehiclesand the like where the available area in one direction is limited.

3. In an acoustical device, a substantially conical diaphragm having asubstantially oblong effective outside periphery including a pair ofparallel sides.

4. In an acoustical device, a substantially 140 dish-shaped diaphragmhaving a substantially oblong periphery including two relatively longparallel sides. I

5. In an acoustical device, a substantially dish-shaped diaphragmshaped, to provide a sub- 145 stantially oblong effective outsideperiphery including two spaced relatively long parallel sides.

6. In an acoustical device, a substantially conical tympanum having asubstantially oblong periphery including at least two parallel sides,150

Iro

the longer dimension of the oblong being approximately twice the shorterdimension thereof.

7. In an acoustical device 01' the class described, a substantiallyconical diaphragm provided with a substantially oblong periphery, thelong sides of the periphery being dished in the direction of the apex ofthe cone.

8. In an acoustical device of the class described, a substantiallyconical diaphragm having a substantially oblong periphery providing twospaced relatively long parallel sides, and flexible mounting stripssecured to the periphery of the diaphragm.

' 9. In an acoustical device of the class described, a substantiallyconical diaphragm shaped to provide a substantially oblong periphery,flexible mounting strips secured to the long peripheral sides of thediaphragm, and other flexible mounting strips secured to the shortperipheral sides 0! the diaphragm.

10. In an acoustical device of the class described, a substantiallyconical tympanum shaped to provide a substantially oblong periphery, andseparate flexible mounting strips formed integrally with the peripheraledge of the diaphragm.

11. In an acoustical device of the class described, a substantiallyconical tympanum shaped to provide a substantially oblong periphery, anda continuous flexible mounting strip formed integrally with theperiphery of said diaphragm.

CARL M. TICI-IENOR. BYRON C. BOOTH.

